Generally, an amateur golfer makes efforts for improving his/her golf score as much as possible, for example, by trying to increase the number of rounds in golf courses as well as the number of practice golf swings and the number of golf balls to be hit at a driving range, so as to develop his/her skill, and purchasing an expensive golf club so as to increase a carry distance of a hit golf ball. However, as for the carry distance, it is difficult to have a desired effect, in many cases.
In the above situations, there has recently been a golf swing simulation apparatus (see, for example, the following Patent Document 1). There has also been a golf swing practicing apparatus for learning an ideal posture between a setup position before a swing and a finish position after the swing (see, for example, the following Patent Document 2).
Further, as a training apparatus for actively strengthening muscles necessary during a golf swing (golf swing muscles), there has been a muscle-strengthening training apparatus which comprises: a rotational-load applying device; and a handle including a spirally-twisted stainless-steel rod member fixed to the rotational-load applying device and a grip pivotally attached to a bendable distal end of the rod member, wherein the rotational-load applying device is adapted to apply a rotational load when a user moves the grip of the handle from a backswing position to an impact position for hitting a golf ball (see, for example, the following Patent Document 3).
Furthermore, there has been a golf swing practicing apparatus comprising a swinging-movement control device connected to a grip through a swing arm and an intermediate arm, wherein a resistance or load based on an operating oil within the swinging-movement control device is increased in a course of a swinging movement of the swing arm along with a downswing where a user moves the grip from a backswing position to a lowermost position as a golf-ball hitting position (see, for example, the following Patent Document 4).
The above golf swing practicing apparatuses intended to strengthen the golf swing muscles include various types having a compact structure and a large-scale or complicated structure. However, in all of the apparatuses, the load for strengthening the muscles is constant, and it is impossible to adjust the load depending on individual differences in physical strength.